Chapter 13.04


13.04.010    Regulations generally.

13.04.020    County specifications – Adoption authority – Availability.

13.04.030    Sewage disposal permit – Plans and specifications required.

13.04.040    Sewage disposal permit – Required – Fee.

13.04.050    Installer’s permit – Required – Terms.

13.04.060    Installer’s permit – Suspension or revocation.

13.04.070    Inspection of systems.

13.04.080    Individual sewage disposal systems – Location.

13.04.090    Individual sewage disposal systems – Capacity.

13.04.100    Septic tank design and construction.

13.04.110    Absorption fields.

13.04.120    Seepage pits.

13.04.010 Regulations generally.

A. No person shall occupy as a place of habitation any building, dwelling, or vehicle unless adequate and sanitary facilities for the disposal of sewage shall have been provided in conformance with this chapter.

B. Every building in which plumbing fixtures are installed, and all premises having drainage piping therein, located where no public sanitary sewer is reasonably available, shall be connected to a sewage disposal system approved by the county health department. All such buildings and premises shall be connected to a public sanitary sewer wherever such sewer is reasonably available.

C. All human excreta and other sewage and liquid household wastes shall be disposed of in a properly designed, constructed, and maintained sewage disposal system approved by the county health department.

D. Sewage shall not be permitted to drain directly or indirectly into any natural or artificial body of water; cesspool; well, whether in use or abandoned; or upon the surface of the ground; nor shall sewage be permitted to pollute the groundwater.

E. All sewage disposal systems shall be maintained in accordance with the rules and regulations of the State Board of Health. (Ord. O-383, 1966).

13.04.020 County specifications – Adoption authority – Availability.

A. Specifications relating to sewage disposal systems, including but not limited to location, capacity, septic tank design and construction, absorption fields and seepage pits shall be in accordance with standards adopted by the health officer of the county.

B. Copies of the standards and specifications shall be available in the county health department and shall be supplied without charge to anyone upon request. (Ord. O-383, 1966).

13.04.030 Sewage disposal permit – Plans and specifications required.

Plans and specifications for the new construction of a sewage disposal system or for the alteration of an existing system must be submitted to the county health department, with an application for a permit for such construction or alteration, prior to the beginning of such construction or alteration. (Ord. O-383, 1966).

13.04.040 Sewage disposal permit – Required – Fee.

A. It is unlawful to begin or perform any work in the construction or alteration of any sewage disposal system without complying with all of the provisions of this chapter and without having a permit from the health department for such work.

B. The fee for each sewage disposal permit shall be in accordance with a schedule determined by the county board of health. (Res. 66-73, Z-565, 1973; Res. U-461, 1969; Ord. O-383, 1966).

13.04.050 Installer’s permit – Required – Terms.

A. It is unlawful and a violation of this chapter for any individual, firm, corporation, or association to engage in the business of installation, alteration, and/or repair of individual sewage disposal systems without possessing a valid sewage disposal system installer’s permit; hereinafter called installer’s permit; provided, that an installer’s permit shall not be required of any owner installing or repairing an individual sewage disposal system upon his own property for his own residential occupancy.

B. No installer’s permit granted under this chapter shall be transferable.

C. Application for such permit shall be made to the health officer on forms provided by him and available at the county health department. The applicant shall, when requested, demonstrate to the health officer or his authorized representative sufficient knowledge of the principle of septic tank operation and sanitation and of this chapter by examination or otherwise.

D. Prior to issuance of an installer’s permit the applicant must provide a surety bond approved as to form by the county prosecuting attorney in the minimum of $2,000 or other bond approved by the prosecuting attorney or executed by a surety company duly authorized to do business in the state of Washington and the county. The bond shall be conditioned that the holder of the installer’s permit and his agents in performing work governed by the regulation shall exercise all reasonable care and skill and shall fully comply with all the provisions of this chapter.

E. Each installer’s permit shall be issued for one year and shall expire March 31st of each year. The permit fee shall be in accordance with a schedule determined by the county board of health. (Res. 66-73, Z-565, 1973; Res. U-461, 1969).

13.04.060 Installer’s permit – Suspension or revocation.

Any installer’s permit issued pursuant to this chapter may be suspended or revoked by the health officer if, after a hearing, he finds incompetency, negligence, misrepresentation in making application for a permit to construct or install a sewage disposal system, or failure to comply with the provisions of this chapter. (Res. U-461, 1969).

13.04.070 Inspection of systems.

A. All sewage disposal system construction or alteration shall be inspected and approved by the health officer or his authorized representative; provided, the health officer may, in his discretion, approve any project without inspection.

B. When the system is ready for inspection, the health department shall be notified, and all portions of the system left open and uncovered for inspection and approval. If any portion of the system is covered before it is inspected and approved, the same shall be uncovered for inspection when ordered by the health officer or his authorized representative. (Ord. O-383, 1966).

13.04.080 Individual sewage disposal systems – Location.

Septic tanks, seepage pits, and absorption fields shall be located in accordance with the following minimum distances in feet:


Septic Tank

Seepage Pit

Absorption Field





Property line




Foundation wall




Water lines




Seepage pit



Stream or lake




Distribution box


High ground-

water level



below bottom

of tank

13.04.090 Individual sewage disposal systems – Capacity.

Minimum design capacity of septic tanks for individual homes shall be as follows:

Number of Bedrooms


1 – 2






Per additional bedroom:

250 additional.

(Ord. O-383, 1966).

13.04.100 Septic tank design and construction.

A. The septic tank shall be constructed of durable, watertight material not subject to excessive corrosion or decay.

B. Poured concrete tanks shall be sufficiently reinforced. All sides and the bottom shall be at least four inches thick. Tops of septic tanks and seepage pits shall be made of at least five inches of reinforced concrete.

C. Concrete block tanks shall be laid on a poured concrete floor not less than four inches thick with the walls waterproofed with a cement mortar, asphalt tar emulsion or other waterproofing material approved by the health department.

D. The minimum wall thickness of any steel tank shall be No. 12 U.S. Gauge (.109) and each such tank shall be protected from corrosion externally and internally by an approved bituminous coating or by other acceptable means.

E. The liquid depth of the tank shall not be less than 30 inches. A liquid depth greater than six feet shall not be considered in determining the capacity of the tank.

F. Standard inlet and outlet tees or baffles shall be located at opposite ends of the tank and tees shall be at least four inches in diameter. The inlet tee or baffle shall project below the liquid surface at least six inches and not more than 12 inches and above the liquid surface at least to the crown of the inlet sewer. The outlet tee or baffle shall project below the liquid level 40 percent of the liquid depth and at least four inches above the crown of the inlet sewer. Scum storage volume (space between the liquid surface and the top of inlet and outlet devices) shall be not less than 15 percent of the required liquid capacity. The inlet invert shall be at least one inch above the outlet invert. There shall be at least one inch between the underside of the top of the tank and the top of the inlet and outlet tees or baffles.

G. Adequate access to each compartment of the tank shall be provided by a manhole of at least 18 inches diameter or width. Provision shall be made for direct access from outside the tank to inlet and outlet tees or baffles.

H. Tops of septic tanks shall be not less than four inches or more than 18 inches below finished grade, unless the manhole is built up to within 18 inches of the finished grade. (Ord. O-383, 1966).

13.04.110 Absorption fields.

A. All fields shall consist of a minimum of at least two lateral lines, of no more than 100 feet in length, as follows:

1. Lines: at least two;

2. Length: not more than 100 feet;

3. Depth, tile lines (bottom): 18 to 36 inches;

4. Width of trench: 18 to 36 inches;

5. Slope of tile: not over 6 inches per 100 feet;

6. Depth of coarse material:

a. Under pipe: at least 12 inches;

b. Over pipe: at least 2 inches;

7. Depth of backfill: at least 12 inches over coarse material.

B. If there are more than two lines of tiles, a distribution box must be used.

C. Filter material shall be of crushed stone, gravel, slag or other material of equivalent strength and durability, from one-half inch to two and one-half inches in diameter and free from fines, dust, sand or clay. It shall completely encase the tile or perforated pipe. The sections of tile or perforated pipe shall have openings between joints no greater than one-half inch, and these openings shall be protected to eliminate soil infiltration. An effective barrier such as untreated building paper, hay or straw shall be placed over the filter material to prevent infiltration of the backfill. (Ord. O-383, 1966).

13.04.120 Seepage pits.

A. Use of seepage pits with septic tanks is acceptable only when soil conditions or topography indicate a need for this method of disposal. Seepage pits may not be used in localities where shallow wells are used.

B. Effective absorption area of a seepage pit shall be calculated as the side area, below the inlet, exclusive of any hardpan, rock, or clay formations. The minimum absorption area must be 150 square feet per bedroom.

C. No pit excavation may extend into the water table where groundwater is encountered. The bottom of the pit shall be backfilled with clean, coarse sand at least two feet above the high water table.

D. Cast iron pipe with tight joints shall be used to connect the septic tank to the pit.

E. All seepage pits shall be lined with brick, stone, cement block or other durable material.

F. The annular space between the lining and the earth wall shall be filled with rock or gravel.

G. An adequate cover shall be provided for the seepage pit of concrete or steel.

H. Seepage pits must be located in a protected area where they will not be subject to being driven over by automobiles or other equipment. (Ord. O-383, 1966).